Heating blanket or the like and method of fabricating same



Aprii 2o, 194s.,

HEATI A. J, HUCK 2,439,892

NG BLANKET OR THE lLIKE AND METHOD 0F FABRICATING SAME y Filed Aug. 29, 1944 NVENTOR.

. element in its nnal aaixnteel Apr. 20, l 1948 AffreaJfnucn ist. Lon

assignments, to Knapp Louis, Mo., a corporati is, Mo, ,'fassignor, liy'niesne -Monarch )Comp any, 'St. on' of Delaware IApiil'if'atim August 29, 1944,` sralNofilize 4 claims. (01.219446) 'My present invention relatesfto aheating pad 'having a novel low cost heating element arrangeiment especially adaptedrfor blanket size pads, and to a method fortraversing the heating ele- ;ment with respect totheblanket One object of the invention is tovprovide a s imj ple means Afor threading the heating element :through a, backing sheet which takesa minimum of time and results in the heating element being .arranged in short sections, with the sections so ,spaced that they do not come in contact with each other during normal use of the blanlet.

Another object is to provide a method of lthreading the heating element throughtubes that are inserted into pierced openings of the backing sheet while it is gathered in an accordion-like fashion the' heating element being roved raround pulleys during thev threading process and the pulleys thereafter being spread apar-t, following vwhich the backing sheet can Vbe partially straight' ene'd Vto a substantially nat position and the heat- I ing velement removed from the pulleys so that it will cover substantially the entire area of the backing sheet in its fully stretched position.

With these and other objects in view, my in- `v ention consists in the construction, arrangement and combination of the various parts of my ,heating blanket and inthe steps of my method whereby the objects contemplated are attained as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawings, wherein: Figure 1 is a perspective view of a backing sheet folded in corrugated manner and being periodically pierce-d by piercingelements in accordance with the first stepofmy method.V

Figure 2 is a sectional View as on the line 2 2 yof Figure 1 showing the piercing element through the folded. backing sheet `therewithfor following the needle as it is retracted.

Figure 3 isa similar sectional view through the folded backing sheet with the sleeve therein.

Figure 4 is a perspective view showing a further step in my method with the heating element threaded through the folded backing sheet and roved on pulleys in close coupled relation to 'the backing sheet.

Figure 5 illustrates the pulleys extended to a.

lfar coupled relation with respect to the folded "backing sheet.

Figure 6 illustrates the backing sheet partialfly extended just prior to removal of the heating element from the pulleys.

I Figure 7 is a perspective view showing the cking sheet fully extended and the heating position in relation thereto,

and

Figure 8 is a sectional view through the completed heating blanket showing the backing sheet and a sleeve associated and heating elementen'close'd between two cover sheets.l t On the accompanyinglrawng I haveused the reference character y1?, toindi'catej'a backing sheet 'and' HE a heating element. vThe heating element HE`may be formed ofja' stranded resistance wire having a suitable flexible insulation such as Vinylite thereon, having both electricity and heating insulation `properties The surface 'of the heating element is"p`r efera bly smooth to'facilitate the threading tljiereofV through the backing sheet as will hereinafter appear. 1

The backingv sheet for my'blanket may be Vmade of cloth material, preferably loose jwoven of fibre glass, cotton vor 4asbestosfibres` although it is possible to use such materialsfas laminated rubber sheeting or thin iiex'ible plastic'sheeting. The heating element HE, itwfill be noted by reference to Figure 7, is threaded throughthe' backing sheet in such manner'as'topass' z'ig' 'zag 'across substantially the. entire area thereof' in 'a plurality of and lower cover sheets of blanket like material or the like I0 and l2 The casing Ill-l2 is preferably removable for cleaning without subjecting the backingl sheet and heating element to the cleaning process. For this purpose a suitable separable fastener Hl or similar means may be provided.

To eliminate the necessityofl using a needle to thread the heatingelement through the backing sheet, which process would take considerable time and be impractical because of pulling the entirelength of .heating element back and forth through :the backing sheet, I have devised a method of inserting the heating element so that it can take the position'of'Figure 7 in the final step of the method'and the'operation can be performed in a minimum of time.

` My method involves' asa r'sts'tep, the folding of the backing sheet into"a"corrugated or accordion-like shapeas shown' in 'Figure 1. The backing sheet, while held compressed is then pierced at periodic vpoints as with needles IB and the needles are followed as they are retracted by tubes orsleeves- I8 asin Fgu're'2. The sleeves assume the position shown inFigure 3 providing a passageway for the heating element. The needles I6 `and the sleeve vI8 are, of course, supported by suitable mechanism ina machine and the machine itself can be made in many different ways and still accomplish the steps of my method,

lWhile the sleeves I8 are in the folded blanket, the heating element HE is threaded back and forth through the sleeves, being ,wound from a spool 20. A plurality of pulleys 22 and 24 are located adjacent opposite ends of the sleeves |8 and may be supported ably mounted in the machine and in the arran'geby bars 26 or the like suitment shown in Figure 4. The pulleys in'this figu-re may be considered as in close coupled relation to the folded backing sheet. The forwardl end of theY heating element is threaded through the sleeves and roved on the pulleys and finally anchored as to a pin 28.

The next step in the method is to move one of the bars 2B to a definite distance apart with relation to the other bar as shown in Figure 5. The pulleys 22 and 24 are preferably mounted on ball bearings to minimizevfriction so that the heating element will be expanded and reeled from the spool 2U during .the spreading of the bars. While the bars 26 are being moved relatively apart, the spool 20 spins rapidly to feed the required amount -ofheating element around the entire train of pulleys and through the sleeves I8. This provides a predetermined length of heating resistance and a predetermined wattage for the heating blanket.

rlhe sleeves I8' are then removed from the backing sheet and the heating elements. The

K sleeves are split along one side for this purpose,

the slots being designated I9. i

The backing sheet B may now be partially straightened to the position shown in Figure 6 and the bends 30 of the heating element removed from the pulleys 22 and 24, after which the backing sheet may be extended fully to the substansheet to an accordion-like position simplifies the passage of the heating element through the several layers of the sheet and the pulley arrangement permits a ready support for the heating element during this step of the process and a means to expand the heating element to its final size.

tially flat position of Figure 7 whereupon the l heating element assumes its final and proper position in relation to the backing sheet. With the bars 25 spread the proper distance in Figure 5, the bends 39 of the heating element will extend from one traverse to the next without sagging and without the heating element keeping the backing sheet from assuming its full length. At about the same time, the machine can be readily adjusted to take care of a great variation in size of backing sheet.

From the foregoing specification, it will be obvious that I have provided a simply operable means to thread a relatively long heating element through a sizable expanse of backing sheet such as one the size of a blanket. The resulting product is a relatively low cost heating pad which eliminates all sewing operations. The heating element is supported by periodic passage through theA backing sheet and the points of passage are spaced soas to prevent the sections of the heating element between the points from sagging to such an extent that they contact with each other during normal use of the blanket.

Thus, the blanket vmay be produced by my method `with a minimum of labor and at much less expense thanwith Vprevious methods such as sewing an insulated heating element to the backing sheet or weaving the heating element directly into the backing sheet as a warp or woof thread thereof, Furthermore, Vsewing the heating element to a blanket size backing sheet is impractical on the usual heating element sewing machines for heating pads. Itis also hard to handle such a large assemblage ofgmaterials on any sewing machine, even if its feed table were made relatively large. v j Y With my method the collapsing of the backing Some changes may be made in the construction and arrangement of the parts of my device and in the steps of my method Without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure, use of mechanical equivalents or use of mechanically equivalent method steps which may be reasonably included within their scope Without sacrificing any of the advantages thereof. v

I claim as my invention: Y

l. A methodof supporting a heating element on a backing sheet comprising the steps of folding the backing sheet in a corrugated manner, piercing the folded backing sheet at substantially equally spaced points substantially half way between the foldedl edges thereof, passing the heating element zig-zag through the piercings and in close coupled relation to the folded backing sheet, extending the bends of the heating element to a further coupled position relative to the folded backing sheet, and straightening the backing sheet to a substantial flat position.

2. A method of threading a heating element through a backing sheet comprising the steps of folding the backing sheet in accordion fashion, piercing the folded backing sheet at spaced points, passing the heating element back and forth through the piercings and in'close coupled relation to the folded backing sheet, extending the bends of the heating element to a further coupled position relative to the folded backing sheet, and straightening out the backing sheet.

3. In a method of mounting a heating element on avbacking sheet, the steps of folding the backing sheet to corrugated shape, piercing the folded backing sheet at spaced points substantially half way between the folded edges thereof, passing the heating element zig-zag through the piercings, and extending the backing Sheet to a substantial flat position. Y' Y 4. In a method of forming a heating blanket or the like, the steps of folding a backing sheet to corrugated shape, piercing the folded backing sheet at spaced points, passing a heating element zig-zag through the piercings, extending the backing sheet to a substantial flat position, and covering opposite sides of the backing sheet to enclose the exposed portions of the heating element.

ALFRED J. HUCK.

REFERBEINCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Y' Neff Jan. 5, 1943 

